Spark plug



Sept. 12, 1933. M M, SEYMOUR 1,926,183

SPARK PLUG Filed OCb. 5, 1931 Invenlor /V/V.Sav/721011,;A

Patented Sept. 12, 1933 UNITED STATES PATENT OFFICE f 1 Claim.

This invention relates to a spark plug, the general object of the invention being to provide means whereby the negative electrode can be removed and a new one substituted therefor when the old one becomes burned and pitted.

This invention also consists in certain other features of construction and in the combination and arrangement of the several parts to be hereinafter fully described, illustrated in the accompanying drawing and specically pointed out in the appended claim.

In describing the invention in detail, reference will be had to the accompanying drawing wherein like characters denote like or corresponding parts throughout the several views, and in which:-

Figure l is an elevation of the improved plug.

Fig. 2 is a section on line 2-2 of Fig. 1.

Fig. 3 is a section on line 3-3 of Fig. 2.

In these views, the shell of the plug is shown at 1 and the threaded part thereof is shown at 2, the porcelain body being shown at 3 and the central electrode at 4. In carrying out my invention, I form an exterior groove 5 in the lower 5 cylindrical part 6 of the threaded portion 2, the

groove passing almost entirely around the cylindrical part, but having its ends spaced apart as shown in Fig. 1. A notch 7 extends from one end of the groove thru the lower end of the shell.

A split ring 8 is placed in the groove and has one end rst bent downwardly to pass through the notch 7 as shown at 9 and then this endis bent as at 10 to extend towards the lower end of the main electrode 4 so as to provide the negative electrode. Of course the groove must be made deep enough to so receive the split ring, that this ring will not interfere with the placing (Cl. 12S-169) of the plug in the hole provided for it in the motor.

The resiliency of the wire from which the ring is made will hold the ring in the groove and when the part 10 has become pitted and burned, it is simply necessary to pull the ring from the groove and substitute a new one, so that the electrode can be renewed Whenever desired Without distorting the entire plug.

It is thought from the foregoing description that the advantages and novel features of the invention will be readily apparent.

It is to be understood that changes may be made in the4 construction and in the combination and arrangement of the several parts provided that such changes fall within the scope of the appended claim. l

Having thus described my invention, what-I claim as new isz A spark plug including a shell having an exterior threaded part terminating in a plain cylindrical part, said part having an exterior substantially annular groove, with the ends of the groove spaced apart and a vertical notch extending from one end of the groove through the end ofthe cylindrical part and a resilient split ring tting in the groove and held therein by its resiliency, said ring having its ends engaging the end walls of the groove'and said ring having a bent part connected to one end thereof, said bent part passing downwardly through-v the notch with its lower end bent and contacting a portion of the lower edge of the shell and extending toward the main electrode to form a removable negative electrode.

MORGAN MED SEYMOUR. 

